Color-color Relations for Red Giants in Star Clusters
Abstract
New Johnson-Cousins UBVRI photometry of giants in globular clusters is combined with JHK photometry on the CIT system to produce color sequences for giants from the globular clusters M3, M5, M13, and M92. UBVRI data are also presented for giants in the metal-rich open cluster NGC 6791. These data fill a gap in the literature, especially for the R & I bands. We provide the empirical relations between broad band colors for various [Fe/H] values for metal-poor giants. The color sequences for U-B and B-V show clear separations for different [Fe/H] values. We also find weak, though unexpected, metallicity dependences of V-R, V-I, and J-K colors. H-K is metal-insensitive. The above colors are plotted as a function of V-K, and a literature (V-K) - T_{eff} relation is given.
Keywords
Cite
@article{arxiv.astro-ph/9804001,
title = {Color-color Relations for Red Giants in Star Clusters},
author = {Kaspar von Braun and Kristin Chiboucas and Jocelyn Kelly Minske and Jose Francisco Salgado and Guy Worthey},
journal= {arXiv preprint arXiv:astro-ph/9804001},
year = {2009}
}
Comments
21 pages, 7 figures; AASTeX 4.0; to appear in the July 1998 edition of PASP. Revised version; includes discussion on possible effects of reddening errors